1. Field of the Invention
The present invention relates to a liquid droplet jetting apparatus which jets liquid droplets onto a recording medium.
2. Description of the Related Art
In an ink-jet recording apparatus which is a liquid droplet jetting apparatus, it has hitherto been known that when a viscosity of an ink near nozzles increases due to drying, or when impurities such as dust are adhered on an opening surface of the nozzles, a bending of jetting (a deflection in direction of jetting) and blocking of nozzles occur, thereby imparting an adverse effect on a jetting performance. Therefore, in conventional ink-jet recording apparatus, when a jetting head is waiting for a jetting command, or when an electric power supply of an apparatus has been put OFF, a nozzle opening surface of the jetting head is covered by a cap.
In such an ink-jet recording apparatus, since a vacuum pump is connected to the cap, with the nozzle opening surface in a state of being covered by the cap, it is possible to carry out suction for forcibly discharging defective ink (such as dry ink) from the nozzle. For carrying out the suction, since it is necessary that the cap is in a close contact with the nozzle opening surface, a bias applying mechanism which applies a bias to the cap toward the nozzle opening surface is provided.
Generally, a carriage on which the jetting head is mounted is not fixed to a guide member such that the carriage is moved slidably on the guide member, and when the nozzle opening surface is covered by the cap, a force which moves the jetting head together with the carriage in a direction of the bias applied is exerted by a bias applying member which applies the bias on the cap toward the nozzle opening surface. When no force resisting the force moving the jetting head acts on the carriage, it is not possible to bring the cap in a close contact with the nozzle opening surface, resulting in an insufficient suction force at the time of suction, or a variation in the suction force. Therefore, a regulating portion is provided in advance at a position at which the carriage makes a contact when moved, and the carriage is regulated to stay without being moved by the movement of the cap, in a state of being covered by the cap, and an arrangement is made such that the cap is deformed assuredly, and is in a close contact with the nozzle opening surface.
When the nozzle opening surface is covered by the cap as described above, the carriage is displaced together with the cap, and an impact when the carriage hits the regulating portion is transmitted to the jetting head.
Therefore, when the jetting head is displaced together with the carriage, sometimes a meniscus is destroyed by the impact when abutted with the regulating portion. In this case, when an attempt is made to jet an ink onto a paper by the subsequent operation, since the meniscus is not formed properly, a jetting defect occurs.